1. Field of the Invention
This invention relates generally to guideways for endoluminal access and more specifically to surgical access devices adapted to introduce surgical instrumentation into body conduits.
2. Discussion of the Prior Art
Surgical access devices of the prior art typically include a sheath having an outside diameter and an inside diameter. An obturator or dilator is inserted into the sheath to facilitate introduction of the sheath into the body conduit. Once the sheath is positioned, the obturator is removed leaving a working channel for surgical instrumentation.
Particularly in the field of urology, the sheath has been provided in the form of an elongate tube having an axis extending between a proximal end and a distal end. The diameter of the tube is generally constant, except for a reduced diameter segment at the distal end. Although the obturator has had an enlarged structure at its proximal end, there has been no such enlargement for the sheath. This has presented a problem as the sheath has tended to migrate distally and disappear beneath the urethral meatus. Representative of this art is the FLEXIBLE URETEROSCOPE SHEATH manufactured and sold by Cook Urological Incorporated.
Access devices particularly adapted for other body conduits have had enlargements at the proximal end, but these have not been specifically configured to prevent migration or facilitate the introduction of instrumentation. Representative of this art are the xe2x80x9cbanana peelxe2x80x9d sheaths which split axially for removal after catheter placement.
During the introduction and removal of dilators, obturators, and instrumentation into and out of a sheath, it is always desirable to facilitate maintenance of the sheath in a relatively stationary orientation. In the past, there has been no handle structure which was sized and shaped to accommodate engagement by a user""s hand disposed in its natural position with the palm facing the user. Nor has there been any progressive funnel structure which would facilitate the introduction of instrumentation into the working channel of the sheath.
These deficiencies of the prior art have been eliminated with the present access device which includes a sheath having at its proximal end a handle specifically adapted to inhibit migration and facilitate use with instrumentation. The handle is formed as a radial enlargement having a distally-facing surface and a proximally-facing surface. The distally-facing surface has a generally concave configuration which provides a gradual enlargement inhibiting migration of the sheath into the ureter. The concave configuration is sized to receive adjacent fingers of a user""s hand disposed in its natural position, in order to facilitate the stationary orientation of the sheath. The concave, distally-facing surface is continuous around the axis of the sheath so that the advantage of this concave configuration can be appreciated regardless of the radial orientation of the sheath.
The proximal-facing surface has a generally convex configuration providing for an increased funneling of an instrument as it is inserted into the working channel of the sheath. Both the distally-facing surface and the proximally-facing surface extend radially inwardly with progressively equal distal positions along the sheath. This provides the handle with the general shape of the bell of a horn. This configuration is not only ergonomically comfortable, but highly practical in addressing the problems of migration, as well as instrument insertion and removal.
The handle can be provided with characteristics permitting the handle to be moved to a preferred position along the tube of the sheath, and then to be fixed to the tube at that preferred location. This makes it possible to provide the sheath with any desired length, even after it has been inserted into the body conduit. A metal structure such as a spring, can be molded into the tube of the sheath to facilitate kink resistance.
The inner dilator can be provided with a Luerlock end, permitting attachment of a sidearm adaptor (not shown). This allows for installation of contrast during sheath placement without the need to remove the guidewire.
These and other features and advantages of the invention will become more apparent with a description of preferred embodiments and reference to the associated drawings.